Two Egyptian military personnel and six militants were killed in the restive North Sinai region, the army said, in the fourth day of a fresh operation by Egypt's air and ground forces to strike insurgents based there.

The attacks on Tuesday come as part of a new campaign launched by the army to fight militants in the area after a Friday attack on an army checkpoint in the Bir Al-Abd area west of El-Arish, the capital of North Sinai, killed 12 soldiers and wounded at least six others.

Egyptian air forces and artillery brigade pounded seven militant hideouts on Tuesday, and damaged 16 havens and arms caches used by the insurgents, the military said in a statement late in the day.

The raids left six militants and two soldiers dead, it added.

Since Friday’s attack, the army said it has killed over 50 militants in retaliation.

Egyptian forces have in recent years been battling an Islamist insurgency based in parts of the northern Sinai region, which has mainly targeted police and troops.

Egyptian President Abdel-Fattah El-Sisi said in an interview with three public newspapers published on Saturday that his country's war against Islamic militants in the Sinai Peninsula would be long, but that conditions in the mountainous, thinly populated region were improving.

"The terrorists are evolving and we are improving our operations," he said.